1. Field of the Invention
The present invention relates generally to the field of endoscopy and specifically to endoscopic apparatus used for endoscopic procedures during which a flexible tube is inserted into the rectum and colon for examination of the colon interior for abnormalities. More particularly, the present invention refers to a control system for supplying a fluid medium, e.g. air, carbon dioxide, water, to the endoscope.
2. Summary of the Prior Art
Endoscopes employing inflatable flexible sleeves for propulsion of the endoscope within a patient's colon are known in the art. Voloshin (U.S. Pat. No. 6,485,409) discloses an endoscope with an endoscopic probe, a bending section for directing the probe within the colon (steering unit), an insertion tube and a flexible covering sleeve or a sheath, which is coupled proximally to the probe. The sleeve is attached to the endoscope in such a manner that its folded section is retained between a cap and an internal spindle, which are located at the rear part of the probe. When inflated, the folded section unfolds over a flange of the internal spindle and an inner portion of the sleeve is pulled behind the steering unit in a distal direction.
Eizenfeld (WO 2004/016299; International application PCT/IL2003/000661) describes an endoscope employing a flexible inflatable sleeve, which before inflation is retained within a dispenser. The dispenser employed in this endoscope has entry and exit ports, defining a transit passage through which the endoscope may pass. The dispenser is adapted to capture the sleeve as the endoscope is retracted through the transit passage in a proximal direction. In another embodiment, the dispenser includes an external sleeve fixed to the dispenser and this external sleeve is adapted to be extended from the dispenser when the endoscope is retracted, so that the external sleeve covers the flexible sleeve. By virtue of this provision any contamination on the flexible sleeve is retained within the external sleeve and does not contact the endoscope or any other objects or areas outside the patient's body. After the endoscope has been removed entirely from the flexible sleeve, the dispenser together with the external sleeve and flexible sleeve is discarded.
It is mentioned in the above reference that the endoscope is provided with an internal sleeve, which is also known as a multi-lumen tubing, since it is usually fitted with appropriate passages or lumens as required for irrigation, ventilation, suction and for passing endoscopic tools there through. The proximal end of the multi-lumen tubing is detachably connected via a dedicated connector, or so called hub, to a source of fluid medium and vacuum. A fluid control system is provided, which comprises an external control unit with a pump for supplying compressed air, a flask for supplying water and a pump for producing vacuum. The control unit is provided also with several pinch valves, which control the supply of the compressed air, water and vacuum to the multi-lumen tubing and compressed air to the inflatable sleeve.
As taught in the parent application Aizenfeld (US 2006/0052665), there is disclosed a new and improved control system and system control unit for supplying fluid medium to the multi-lumen tubing and/or to the inflatable sleeve of an endoscope provided with such a sleeve. This endoscope comprises an operation handle and an insertion tube provided with an insufflation channel, an irrigation channel and a suction channel extending there-along. There is a system control unit with at least one source of a first fluid medium, a source for a second fluid medium, and a source for a vacuum. Optionally, a multifunctional connector may be used for bringing the operation handle in fluid and electrical communication with the system control unit. The at least one source of a first fluid medium and the source for the second fluid medium are simultaneously connectable to and disconnectable from the insufflation channel and the irrigation channel. Compressed air is the first fluid medium for insufflation and water is the second fluid medium for irrigation. The compressed air may come from one or more compression pumps.
The use of compressed air during endoscopy does, however, have potential risks. The consequences of barotraumas caused during colonoscopic procedure are well documented; see for example article “A retrospective analysis of secal barotraumas caused by colonoscope air and pressure”, Gastrointestinal Endoscopy, 2005, volume 61, No. 1, 37-45. Accordingly, it is advantageous to use less compressed air, so as to better control any risk of barotraumas.
It is known that the use of carbon dioxide gas can minimize those risks, otherwise presented by the use of compressed air. The teaching of NORCCAP: a randomized trial to assess the safety and efficacy of carbon dioxide versus air insufflations in colonoscopy, M Bretthauer, Gut, 2002; 50 604-607, are incorporated in its entirety herein by reference and it discusses the use of carbon dioxide gas instead of compressed air. Using carbon dioxide causes less patient discomfort and is safer during electrosurgical procedures.